Single-walled carbon nanotubes are a material with many potential applications. For example, the properties of some carbon nanotubes may allow for creation of capacitors with capacitance versus size characteristics that are not readily attainable with traditional materials. More generally, single-walled nanotubes (SWNTs) made of carbon may exhibit either metallic or semiconducting properties, depending on their diameter and crystalline structure.
One current technique for synthesis of carbon nanotubes involves chemical vapor deposition (CVD) on a growth substrate containing metal nanoparticles. Unfortunately, current CVD methods of carbon nanotube synthesis suffer from a lack of control over the size and shape of the nanotubes. Some methods of carbon nanotube production lead to mixtures of single-walled nanotubes and multi-walled nanotubes. Other methods result in production of nanotubes with variations in nanotube shape and size, leading to a lack of control over the properties of the resulting nanotubes.
Obtaining the metal nanoparticles for use in the growth substrate also poses difficulties. Some current techniques may produce particles of a desirable size, but with poor crystallinity or an unpredictable distribution of phases within the nanoparticles. Other techniques suffer from an inability to control the distribution of sizes around a desired nanoparticle size. Still other nanoparticle synthesis techniques require specialized equipment, long processing times, or expensive specialty chemicals.
In order to realize the full potential of carbon nanotubes as an industrial material, what is needed is a method of synthesis for carbon nanotubes capable of producing single-walled nanotubes while maintaining control over the size and properties of the individual nanotubes.